This invention relates to a system and method for encoding objects. More particularly, this invention relates to a system and method for using a laser to place a microscopically visible code on an object.
For various reasons, it may be desirable to place a code on an object, such as an identification code, that can be read only under magnification. Such a code might be useful, for example, in identifying such articles if they are stolen.
Another use of such a code is in certain retail industries, such as the limited distribution cosmetic and fragrance industry. In such industries, distribution of products is limited to certain authorized retailers. However, it is known that some authorized dealers "divert" a portion of their stock to unauthorized dealers. Manufacturers therefore code each product package so that if it is diverted, the manufacturer can determine the identity of the authorized dealer who was the intended recipient of the package when it was shipped by the manufacturer. The manufacturer can then stop doing business with that dealer, or take other action against him. Unfortunately, the diverters have learned many of the coding systems and have devised means to defeat or attempt to defeat them.
In one system, for example, a pattern of fine pinholes is punched into the cardboard carton containing the product. The placement of the pinholes represents a numerical code identifying the dealer for whom the product was intended. The pinhole pattern is relatively easy to find, particularly because mechanical and aesthetic considerations usually limit its placement to the bottom of the carton. Diverters have learned to defeat the pin coding system by cutting out the coded portion of the package and placing an adhesive label over the damaged area or by adding additional pinholes to the pattern. They can also discard the carton and sell the product without it, or they can substitute a new carton for the coded carton.
It therefore would be desirable to be able to encode objects in a way that the code is difficult to detect, to increase the difficulty of finding and altering or obliterating the code.
It also would be desirable to to able to place the same code in multiple and random locations on an object to further decrease the possibility that all codes will be detected.